CN1551605A - Method and apparatus for session control - Google Patents

Method and apparatus for session control Download PDF

Info

Publication number
CN1551605A
CN1551605A CNA2004100456631A CN200410045663A CN1551605A CN 1551605 A CN1551605 A CN 1551605A CN A2004100456631 A CNA2004100456631 A CN A2004100456631A CN 200410045663 A CN200410045663 A CN 200410045663A CN 1551605 A CN1551605 A CN 1551605A
Authority
CN
China
Prior art keywords
session
session request
event information
filter
protected element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CNA2004100456631A
Other languages
Chinese (zh)
Inventor
C����˹̹��ŵ��
C·康斯坦蒂诺夫
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nortel Networks Ltd
Original Assignee
Nortel Networks Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nortel Networks Ltd filed Critical Nortel Networks Ltd
Publication of CN1551605A publication Critical patent/CN1551605A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/12—Avoiding congestion; Recovering from congestion
    • H04L47/122—Avoiding congestion; Recovering from congestion by diverting traffic away from congested entities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/15—Flow control; Congestion control in relation to multipoint traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/24—Traffic characterised by specific attributes, e.g. priority or QoS
    • H04L47/2416—Real-time traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/26—Flow control; Congestion control using explicit feedback to the source, e.g. choke packets
    • H04L47/266—Stopping or restarting the source, e.g. X-on or X-off
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H04L47/74—Admission control; Resource allocation measures in reaction to resource unavailability
    • H04L47/745—Reaction in network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/70—Admission control; Resource allocation
    • H04L47/74—Admission control; Resource allocation measures in reaction to resource unavailability
    • H04L47/746—Reaction triggered by a failure
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/14—Network architectures or network communication protocols for network security for detecting or protecting against malicious traffic
    • H04L63/1441—Countermeasures against malicious traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1096—Supplementary features, e.g. call forwarding or call holding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1101—Session protocols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1101—Session protocols
    • H04L65/1104—Session initiation protocol [SIP]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/14—Session management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/40—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/40—Network security protocols
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/36—Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0016—Arrangements providing connection between exchanges
    • H04Q3/0062—Provisions for network management
    • H04Q3/0091—Congestion or overload control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/02—Network architectures or network communication protocols for network security for separating internal from external traffic, e.g. firewalls
    • H04L63/0227—Filtering policies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/30—Definitions, standards or architectural aspects of layered protocol stacks
    • H04L69/32—Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
    • H04L69/322—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions
    • H04L69/329—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions in the application layer [OSI layer 7]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M3/00—Automatic or semi-automatic exchanges
    • H04M3/22—Arrangements for supervision, monitoring or testing
    • H04M3/36—Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks
    • H04M3/367—Traffic or load control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M7/00—Arrangements for interconnection between switching centres
    • H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
    • H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
    • H04M7/125—Details of gateway equipment

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Business, Economics & Management (AREA)
  • General Business, Economics & Management (AREA)
  • Multimedia (AREA)
  • Computer Hardware Design (AREA)
  • Computing Systems (AREA)
  • General Engineering & Computer Science (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)

Abstract

The present invention provides a session filter associated with an element to be protected in a communication network. Session requests intended for the protected element are processed by the session filter prior to being forwarded to the protected element. The protected element or a device associated therewith will provide event information indicative of undesirable session conditions, such as an overload condition, which necessitates a reduction or stoppage of incoming session requests for the protected element. The session filter will directly or indirectly receive the event information and take steps to reduce or stop the session requests being sent to the protected element. The session filter may filter the incoming session requests for the protected element and selectively send select session requests to the protected element, as well as send system protection responses to minimize the number of new session requests to devices generating or forwarding the incoming session requests.

Description

Be used to talk with the method and apparatus of control
Technical field
The present invention relates to communication, specifically, relate to providing of the dialogue control relevant with communication network.
Background technology
Marked change takes place in the quantity of calling out in the telephone network along with the time, and traditionally, such network is designed to support the peak value call volume level relevant with society or commercial calls pattern.But, some incident that generation surpasses the call volume pattern of the peak level of being supported appears sometimes.The example of incident comprises that refusal is accepted (denial) professional impact in magnanimity call event, the catastrophic event that comprises natural disaster and war-like action and the packet-based network that is triggered by sales promotion or advertising campaign like this.In addition, equipment fault was lost efficacy such as telephone exchange, also can cause call number to surpass network capacity.If also do not discover, such situation will make the network equipment lose efficacy, and the circulation of whole network is caused remarkable influence.
The effect of network dialogue control is, expection less than the influence flat or the malice session request of height conversation water gaging localize, and keep the professional skill of deciding through consultation for the client.Indivedual telephone call offices realize that network dialogue control helps to isolate undesirable session request, and makes the influence to other callings drop to minimum in the node dialogue controlling mechanism in circuit-switched network.Traditionally, in circuit-switched network, utilized two kinds attempt to control or otherwise reduce the mechanism of the call volume that arrives given exchange, tackle overload situations calling network or dialogue control.First kind of mechanism comprises the management of main line group, and it dynamically reduces available number of trunks between the exchange during the overload conditions.Second kind of mechanism provides the screening in the professional transmission point (STP) in the call signaling network, so that according to point code, number of calls etc. setup requests is filtered.
Unfortunately, used these two kinds of mechanism in the circuit-switched network do not have a kind ofly can be used for packet network, because packet-based soft switch does not possess the notion of main line grouping, do not have STP yet.Since their open nature, the easier malicious attack that is subjected to loading execution of packet network in the puppet of dialogue initialization and foundation.For packet network, have only dialogue or overload control to comprise to abandon incoming call message or with representing professional disabled message response session request message.In the previous case, abandoning incoming call message not only influences the initialized trial of dialogue, and influences the dialogue of having set up.The processing that the element that requires to have transshipped with the disabled message response session request of business message adds, and do not provide any therapeutic action to other nodes in the network or element.Therefore, be necessary to develop a kind of protection mechanism, it makes the service provider can limit effectively or prevent that some session request is to the whole group Internet communication.
Summary of the invention
The invention provides element or the relevant session filter of a set of pieces that to protect in a kind of and the communication network.Want before the session request that protected element proposes is being transmitted to protected element, to handle by session filter earlier.Xiang Guan protected element or device or operating personnel will provide event information therewith, and indication need reduce or stop the incoming call session request to protected element such as undesirable dialogue states such as overloads.Session filter receives described event information directly or indirectly, and takes measures to reduce or stop to be sent to the session request of protected element.Session filter can be filtered the incoming call session request that gives protected element, and optionally sends the session request of selecting to protected element, and to the device transmitting system protection response that produces or transmit the incoming call session request.Described event information will provide instruction to reduce, filter or stop to start and transmitting session request.Therefore, when receiving event information, session filter takes appropriate action the number of the incoming call session request that gives protected or a set of pieces is minimized, so that undesirable dialogue state is minimized or it is eliminated fully.
Session filter can be used different criterions, and the information that provides in the event information is provided, judge how to filter session request or with the system protection message response they.Filter session request and may cause session request to reduce to certain level, they are reduced certain percentage, and the control session request, so that the dialogue that belonging to of selected number of given protected element is only set up in assurance.
Session filter the pick of ground is via packet network work, and is more preferably in session initiation protocol (SIP) network and works, and wherein session request is an INVITE, and perhaps system protection message is the sip message of certain form.In addition, session filter can play the call signaling contact between the call signaling network of circuit-switched network and packet network.For example; can be arranged on session filter between PSTN (PSTN) and the SIP network; the session request that wherein is used for PSTN is a call setup message; such as integrated service User Agreement (ISUP) initial address message (IAM), and the system protection message that is used for circuit-switched network is ISUP overload message.
Read with reference to accompanying drawing after the detailed description of preferred embodiment, the professional and technical personnel can be appreciated that scope of the present invention and understands other aspects of the present invention.
Description of drawings
Be included in the specification and constitute its a part of description of drawings several aspects of the present invention, and be used for explaining principle of the present invention together with describing.
Fig. 1 is a block diagram, and expression is according to the network that comprises session filter of first embodiment of the invention;
Fig. 2 is the communication flow diagram of explanation according to the operation of the present invention of first embodiment;
Fig. 3 is a block diagram, and expression is according to the network that comprises session filter of second embodiment of the invention;
Fig. 4 is the communication flow diagram of explanation according to the operation of the present invention of second embodiment;
Fig. 5 is a block diagram, and expression is according to the network that comprises session filter of third embodiment of the invention;
Fig. 6 is the communication flow diagram of explanation according to the operation of the present invention of the 3rd embodiment;
Fig. 7 is a block diagram, and expression is according to the network that comprises session filter of fourth embodiment of the invention; And
Fig. 8 is the communication flow diagram of explanation according to the operation of the present invention of the 4th embodiment.
Embodiment
The embodiment that proposes below represents to make the professional and technical personnel can put into practice the present invention and the required information of optimum way of the present invention is put into practice in explanation.Description below reading in conjunction with the accompanying drawings, the professional and technical personnel will be appreciated that notion of the present invention and recognizes the not application of concrete these notions of discussing here.Should be appreciated that these notions and application are all within the scope of the disclosure and appended claim book.
Referring to Fig. 1, communication environment shown in the figure 10, wherein session filter 12 can be handled from source element 16 and send, and wants the incoming call session request to protected element 14.Described session request is to want to start between protected element 14 and source element 16 request of communication session.Those message after every other message, the especially session establishment needn't be handled by session filter 12.It should be noted that and to connect source element 16, session filter 12 and protected element 14 with networks of different type.
Therefore, session filter 12 plays acting server for the dialogue branch road with protected element 14 foundation.Can connect (provisioning) or dynamically notify protected element 14 existence of session filter 12 by equipment by session filter 12 or other network entities.In the operation, protected element 14 can provide event information to session filter 12 directly or indirectly.Event information will identify the expression session filter and must protect protected element 14 to avoid handling the overload of all or selected session request, perhaps other undesirable dialogue states.Session filter 12 will be used the dialog process rule when receiving event information, determines how to respond all or selected incoming call session request.Processing rule can make session filter 12 that the selection criterion is applied to the incoming call session request, and according to these criterions request is filtered.Follow these rules, session filter 12 can respond the session request that is not transmitted to one or more protected elements, and the system protection response is provided.For example; session filter 12 can be filtered the incoming call request; so that the session request that is sent to protected element 14 is reduced to the level of requirement, the session request that offers protected element 14 is reduced certain percentage, perhaps restriction simultaneously with the number of the dialogue of specific protected element.
When using processing rule and select session request, in event information by protected element 14 identifications or can be used for discerning unaccepted session request by the selected marker that session filter 12 provides.These selection criterions comprise the mark of the identification of expression source element 16 or protected element 14, such as the generic resource identifier in the session request in violation of rules and regulations, the type of dialogue etc.
The event information that protected element 14 offers session filter 12 can only be the information of expression overload or other undesirable states, perhaps can actually provide several parameters: describe state in violation of rules and regulations parameter, select some processing rule parameter, be provided for discerning parameter, the parameter that is given for the filtering technique of session request, the parameter of recognition system protection response or their any combination of the selected marker of session request to be processed.Like this; the complexity of the event information that is provided by protected element 14 can change; and suitably configuration dialog filter 12 and protected element 14 make it to cooperate with one another, and handle the incoming call session request effectively according to the event information that protected element 14 provides.In addition, event information can maybe can be discerned the overload that influences protected element 14 or the device of other undesirable states provides by network operator.
In operation, session filter 12 will receive event information and determine suitable processing rule, be applied to all or selected some session request subsequently.Session filter 12 can be by applying back-pressure to the source element 16 that sends session request or other network element transmitting systems protection response to suitable session request.The system protection response is configured in one section preset time or reduces or stop the transmission of session request indefinitely.Like this, in violation of rules and regulations source element 16 or other network elements will stop to send session request, and the undesirable dialogue state of the protected element 14 that helps to weaken the effect.Session filter 12 is preferably used different criterions to the incoming call session request.Filter criterion and can allow session filter 12 ignore all session request or it is selected simply, wherein uncared-for these session request are not forwarded to protected element 14.Filtration can be based on number of attempt, session request sum, source element 16 etc.Response is from the event information of protected element 14 like this, and session filter 12 can work with the name of protected element 14, helps to alleviate undesirable dialogue state.
In the embodiment that recommends, the communication session of utilizing session initiation protocol (SIP) that a part is set up between protected element 14 and source element 16 is easy to carry out.The SIP specification is in Internet Engineering Task Force ' s Request for Comments (RFC) 3261 (to the Internet engineering duty mandatory requirement of suggestion (RFC) 3261): provide among the SessionInitiation Protocol Internet Draft (session initiation protocol internet draft), described file is whole, and attached this is for referencial use.In general, SIP is in order to set up the medium dialogue between such as any number terminal points such as source and protected elements 16,14.Generally, depend on the configuration of device, these terminal points can be supported the dialogue of data, audio frequency and voice medium or its combination of any number.The SIP terminal point can run application, and generally is called user agent (UA), and described user agent can make the medium dialogue that utilizes SIP be easy to carry out.In certain embodiments, the user agent can register their ability, so that by coming to set up dialogue with sip proxy server to REGISTER message is provided such as the sip proxy server that is provided by session filter 12.REGISTER message makes Universal Resource Locater (URL) notice sip proxy server the SIP network can discern described user agent.The relevant information that how reaches particular user agent by the SIP network, general Internet protocol (IP) address or port by providing the user agent to be used in SIP dialog also are provided REGISTER message.When the user agent wants to set up when dialogue with other user agents, the user agent who initiates dialogue can send INVITE to sip proxy server, and the TO of INVITE head intended target user agent.The form of SIP URL is taked in user agent's identification.Whether sip proxy server will utilize the SIP URL of the TO head of described message to determine that the targeted customer acts on behalf of and login on sip proxy server.Generally, user name is unique in the regulation territory.
If the targeted customer agency logins on sip proxy server, then sip proxy server is directly acted on behalf of the transmission INVITE to the targeted customer.The targeted customer agency will utilize the 200OK message response, sets up dialogue according to the message that requires in the SIP specification between corresponding user agent.As such as INVITE, the parameter that embeds in the session establishment message such as 200 OK and affirmation (ACK) message, transmission medium ability between the user agent of corresponding terminal point.The medium ability can exchange in such as message such as SIP INFO.Medium ability general using session description protocol (SDP) is described.In case terminal point all is in movable dialogue state each other separately, and determined other each ability, then Gui Ding Media Contents can exchange in suitable medium dialog procedure.
According to Internet Engineering Task Force ' s RFC 3261 (the Internet engineering duty force RFC 3261), the user agent is the application program that had not only comprised user agent client but also comprised subscriber proxy server.User agent client refers generally to start the client applications of SIP request, and wherein subscriber proxy server is contact user when receiving the SIP request, and returns the application program of response with user's name.Generally, response receives, rejects or make received request to be redirected.
When realizing SIP, session request generally is an INVITE, and event information can utilize such as NOTIFY, and suitable sip messages such as MESSAGE and INFO send to session filter 12.For described event information, dialogue control can define at sip message, as mentioned above, so that comprise suitable event information.Like this, when receiving event information, 12 necessary dialog process rule application of session filter are in meeting the INVITE of selecting criterion.Session filter 12 can be to source element 16 or other entity send-back systems protection response in sip message; filtration is provided then; wherein all, neither one or only selectively some incoming call INVITE in fact be forwarded to protected element 14, thereby allow to start the dialogue with protected element 14.
Exemplary communication flow process according to the SIP environment of Fig. 1 embodiment is provided among Fig. 2.At first, one or more sources element 16 sends the INVITE of wanting to protected element 14, and wherein INVITE is delivered to session filter 12 (step 100) at first.Supposing for one or more protected elements 14 does not have such as undesirable dialogue states such as overloads, and session filter 12 is transmitted to suitable protected element 14 (step 102) to INVITE.When undesirable state occurring on protected element 14, event information sends to session filter 12 (step 104) directly or indirectly.Suppose that event information indicates undesirable state, and be enough to make session filter 12 the dialog process rule application in meet the INVITE (step 106) of selecting criterion according to described event information.
Depend on the configuration of dialog process rule and event information; session filter 12 is used suitable filtration criterion the incoming call INVITE is filtered (step 108), and can respond all or just uncared-for (getting clogged) INVITE (step 110) with system protection.Like this, because session filter 12 receives extra INVITE from source element 16, have only some INVITE to be forwarded to protected element 14 (step 112).Especially, session filter 12 can play all incoming call INVITE of effective obstruction under some environment, prevents that they are sent to the effect of protected element 14.Therefore, session filter 12 applies buffer brake to the incoming call INVITE effectively by to source element 16 transmitting systems protection response, and wherein system protection message will trigger 16 minimizings of source element or stop to send INVITE.In addition, the INVITE that continues to be sent to protected element 14 is filtered by session filter 12, and further the undesirable dialogue state of protected element 14 is tormented in control.
According to these responses; undesirable dialogue state finally is reduced; like this; after certain period or directly or indirectly from protected element 14 receive the expression undesirable dialogue state no longer exist information the time, session filter 12 can be cancelled buffer brake and filtration (step 114).This moment, session filter 12 will receive the incoming call INVITE, does not add then they are forwarded to protected element 14 (step 116) with filtering.
As mentioned above, system protection message regardless of form or form, can be sent to source element 16 entity in addition, so that help to stop or reducing the number such as session request such as INVITE of wanting to be sent to protected element 14.Referring to Fig. 3, communication environment shown in the figure 10 wherein is provided with session filter 12S with one or more sources element 16 with interrelating, and as mentioned above, session filter 12 and one or more protected elements 14 is interrelated.Like this; the session filter 12S that interrelates with source element 16 can be from the session filter 12P receiving system protection message relevant with protected element 14; and work to provide inceptive filtering to the session request that is derived from source element 16; and provide system protection message to described source element 16, make the session request of wanting to mail to one or more protected elements 14 stop or reducing generation.Correspondingly, be sent to protected element 14 session filter 12P event information can propagate to the suitable session filter 12S that interrelates with source element 16 by packet network 18.Session filter 12S can realize the dialog process rule to be similar to above-mentioned mode.An exemplary communication flow process that is shown in the communication environment 10 of Fig. 3 is shown in Fig. 4.
At first, one or more sources element 16 sends INVITE, wants to start and one or more protected element 14 dialogues.These INVITE are received (step 200) by session filter 12S, and session filter 12S is forwarded to the session filter 12P (step 202) relevant with protected element 14 to described INVITE.Supposing does not have undesirable dialogue state, and session filter 12P will be forwarded to protected element 14 (step 204) to described INVITE.
At some constantly; undesirable dialogue state can appear in protected element 14; so event information is sent to session filter 12P (step 206), the latter the dialog process rule application in meet the INVITE (step 208) of selecting criterion according to event information.Like this, session filter 12P can filter INVITE (step 210) according to suitable filtration criterion, and with the response (step 212) of system protection message conduct to all or some INVITE.Preferably system protection message is sent to the session filter 12S that interrelates with source element 16.
According to system protection message, session filter 12S will be the dialog process rule application in the INVITE (step 216) that receives from source element 16.The dialog process rule can make session filter 12S filtration criterion as requested that INVITE is filtered (step 218), and to source element 16 transmitting systems protection message (step 220).Processing on the session filter 12S is used to provide the preliminary filtration to INVITE once more, and applies preliminary buffer brake, so that the processing on the session filter 12P that further assists to interrelate with protected element 14.Correspondingly; INVITE from source element 16 is tentatively filtered by session filter 12S; INVITE after the filtration is sent to session filter 12P (step 222), and the latter further filters INVITE, and the message after will filtering is sent to protected element 14 (step 224).It should be noted that the INVITE after each that deliver to session filter 12P from session filter 12S is filtered can cause system protection response (step is not shown) from session filter 12P.
From the above, the present invention is to wherein the main packet-based scheme of the communication session between source element 16 and the protected element 14 is obviously favourable.It should be noted that the present invention's advantageous particularly on the node of circuit switching and packet network.Fig. 5 provides how providing session filter 12 that basic explanation is provided on packet network 18 and the node such as PSTN circuit-switched networks 20 such as (PSTN).Session filter 12 will reside in the call treatment zone such as signaling system 7 circuit-switched networks 20 such as (SS7), and the circuit switching of also controlling the gateway that has arrived the dialog interface effect between packet network 18 and the circuit-switched network 20 connects.Therefore, session filter 12 will reside in and can promote on each automatic network on the network entity such as session request such as setup requests or INVITE.The professional and technical personnel can be familiar with the various entities that the dialogue filtering function wherein can be provided.In addition, session filter 12 can provide in mode independently.
Undesirable dialogue state can appear on packet network 18 or the circuit-switched network 20, and session request may need to filter like this, and buffer brake may need to offer packet network 18 or circuit-switched network 20.Fig. 6 and 7 provides the scheme that filtration and buffer brake wherein are provided simultaneously to these two networks.
Specifically referring to Fig. 6, take the session request of INVITE form to produce from packet network 18, undesirable dialogue state appears on the circuit-switched network 20.Undesirable dialogue state may be telephone exchange inefficacy, main line inefficacy etc.At first, produce INVITE and send it to session filter 12 (step 300) at packet network 18.Session filter 12 plays gateway, and the protocol translation of 20 entities from the packet network entity to circuit-switched network is provided effectively.Therefore; session request in the circuit-switched network 20 can be a call setup message; such as integrated service User Agreement (SUP) initial address message (IAM), described initial address message is sent to protected element 14 (not shown) (step 302) of expection by circuit-switched network 20.Like this, arrive the call setup message of the incoming call INVITE generation of session filter 12 by circuit-switched network 20 transmissions.
At some constantly, undesirable dialogue state can appear on the circuit-switched network 20, so suitable event information is sent to session filter 12 (step 304) directly or indirectly.Event information may be an ISUP overload message etc.Respond received event information, session filter 12 will be the dialog process rule application in the INVITE (step 306) that meets any selection criterion that can use according to event information.Therefore, session filter 12 can be filtered INVITE (step 308) and with system protection message response INVITE (step 310).Like this, the INVITE after the filtration will make the call setup message decreased number (step 312) that sends by circuit-switched network 20.This process will continue one selected period or otherwise proceed to always session filter 12 judge no longer need to filter and buffer brake till (step 314), wherein the incoming call INVITE no longer needs to filter, and, send a call setup message (step 316) by circuit-switched network 20 at each INVITE that is received.
Referring to Fig. 7, overload or undesirable dialogue state appear at packet network 18, and produce the session request of taking the call setup message form in circuit-switched network 20.So, be sent to session filter 12 (step 400) such as call setup messages such as ISUP IAM, when not having overload or undesirable dialogue state, session filter 12 will be translated into suitable INVITE to call setup message, and send their (steps 402) by packet network 18 as required.When overload or undesirable dialogue state when occurring, event information is sent to session filter 12 (step 404), so that trigger the dialog process rule application in meeting the call setup message (step 406) that some selects criterion.12 pairs of call setup messages of session filter the filtration (step 408) of any necessity is provided and in circuit-switched network 20 corresponding telephone exchange transmitting system protection message, such as overload or block message (step 410).Like this, be sent to corresponding protected element 14 (step 412) corresponding to those INVITE that are considered suitable for the call setup message of continuation by packet network 18 after the filtration.Once more, in overload or after undesirable dialogue state is eliminated, session filter 12 or time to or respond suitable message, elimination offers the buffer brake and the filtration (step 414) of call setup message, and allows the INVITE (step 416) at each call setup message that will pass through packet network 18 transmissions that receives.
The function of session filter 12 can realize in the device of the type of server of isolating or can realize in the apparatus for grouping that can promote such function of any number or CSU circuit switching unit.Generally, the device of realization session filter 12 is configured to as graphic extension among Fig. 8.Session filter 12 will be relevant with the control system 22 of the memory with the required necessity of software, and described software can be controlled control system, so that realize above-mentioned functions.Described control system 22 is also relevant with one or more communication interfaces, so as to promote with or communicate by letter at packet network 18 or the heterogeneous networks entity on circuit-switched network 20, as described configuration requirement.
The professional and technical personnel can be appreciated that, improvement and the modification of the embodiment that the present invention is recommended.Improvement that all are such and modification all are considered in the scope of disclosed here notion and appended claim book.

Claims (40)

1. one kind for element provides the method for dialogue control, and described method comprises:
A) be received in the session request of setting up dialogue between protected element and at least one the source element;
B) receive the event information of indicating the undesirable state relevant with described protected element;
C) handle described event information,, be forwarded to protected element so that determine some session request of selection; And
D) when receiving described event information, send the session request of selecting to described protected element, wherein optionally the incoming call session request is transmitted to described protected element.
2. the method for claim 1 is characterized in that also comprising transmitting system protection response, and described system protection response is configured to stop or reducing a plurality of session request that produced by described at least one source element.
3. method as claimed in claim 2 is characterized in that: described system protection response is sent to described at least one source element.
4. method as claimed in claim 2 is characterized in that: described system protection response is sent to and the relevant session filter of described at least one source element.
5. method as claimed in claim 2 is characterized in that: described event information is sent to and the relevant session filter of described at least one source element.
6. method as claimed in claim 2 is characterized in that: described session request receives by packet network, and the response of described system protection to be call signaling network by circuit-switched network send.
7. method as claimed in claim 2 is characterized in that: described session request is that the call signaling network by circuit-switched network receives, and the response of described system protection sends by packet network.
8. the method for claim 1, it is characterized in that: described session request is the call setup message from circuit-switched network.
9. the method for claim 1, it is characterized in that: described session request is the session initiation protocol INVITE from the session initiation protocol network.
10. the method for claim 1, it is characterized in that: described event information receives from described protected element.
11. the method for claim 1 is characterized in that: described event information is to receive from described protected element entity in addition.
12. the method for claim 1 is characterized in that: described event information is represented the overload of described protected element.
13. the method for claim 1 is characterized in that: described event information represents to influence the network failure of described protected element.
14. the method for claim 1 is characterized in that: described event information is represented the malice session request of described protected element is attacked.
15. the method for claim 1 is characterized in that: described event information also provides the information of the session request of assisting definite described selection.
16. the method for claim 1 is characterized in that: described event information also provides the information of described at least one the source element of identification, is filtered from the session request of described at least one source element.
17. the method for claim 1 is characterized in that described event information also provides the one group of information that is made of the following:
A) expression can be transmitted to the information of some session request of described protected element;
B) expression is transmitted to the information of minimizing degree of hope of the session request of described protected element; With
C) information of the some dialogues that can support of the described protected element of expression.
18. the method for claim 1 is characterized in that: for some event information, all session request that give described protected element all are blocked.
19. one kind for element provides the session filter of dialogue control, it comprises:
A) at least one interface; With
B) control system, it is relevant with described at least one interface and be suitable for
I) be received in the session request of setting up dialogue between described protected element and described at least one source element;
Ii) receive the event information of the expression undesirable state relevant with described protected element;
Iii) handle described event information,, be forwarded to described protected element so that determine some session request of selection; And
When iv) receiving described event information, send the session request of selecting, wherein, the incoming call session request optionally is transmitted to described protected element to described protected element.
20. session filter as claimed in claim 19 is characterized in that: described control system also is suitable for transmitting system protection response, and described system protection response is configured to stop or reducing the many session request that produced by described at least one source element.
21. session filter as claimed in claim 20 is characterized in that: described system protection response is sent to described at least one source element.
22. session filter as claimed in claim 20 is characterized in that: described system protection response is sent to and the relevant described session filter of described at least one source element.
23. session filter as claimed in claim 20 is characterized in that: described event information is sent to and the relevant described session filter of described at least one source element.
24. session filter as claimed in claim 20 is characterized in that: described session request receives by packet network, and the response of described system protection to be call signaling network by circuit-switched network send.
25. session filter as claimed in claim 20 is characterized in that: described session request is that the call signaling network by circuit-switched network receives, and the response of described system protection sends by packet network.
26. session filter as claimed in claim 19 is characterized in that: described session request is the call setup message from circuit-switched network.
27. session filter as claimed in claim 19 is characterized in that: described session request is the session initiation protocol INVITE from the session initiation protocol network.
28. session filter as claimed in claim 19 is characterized in that: described event information receives from described protected element.
29. session filter as claimed in claim 19 is characterized in that: described event information is to receive from described protected element entity in addition.
30. session filter as claimed in claim 19 is characterized in that: described event information is represented the overload of described protected element.
31. session filter as claimed in claim 19 is characterized in that: described event information represents to influence the network failure of described protected element.
32. session filter as claimed in claim 19 is characterized in that: described event information is represented the malice session request of described protected element is attacked.
33. session filter as claimed in claim 19 is characterized in that: described event information also provides the information of assisting definite session request of selecting.
34. session filter as claimed in claim 19 is characterized in that: described event information also provides the information of described at least one the source element of identification, is filtered from the session request of described at least one source element.
35. session filter as claimed in claim 19 is characterized in that described event information also provides the one group of information that is made of the following:
A) expression can be transmitted to the information of some session request of described protected element;
B) expression is transmitted to the information of minimizing degree of hope of the session request of described protected element; With
C) information of the some session request that can support of the described protected element of expression.
36. session filter as claimed in claim 19 is characterized in that: for some event information, all session request that preparation gives described protected element all are blocked.
37. one kind for element provides the method for dialogue control, described method comprises:
A) be received in the session request of setting up dialogue between protected element and at least one the source element;
B) receive the event information of representing the undesirable state relevant with described protected element;
C) handle described event information, so that determine some session request of selection; And
D) transmitting system protection response, described system protection response are suitable for stopping or reducing the many session request that produced by described at least one source element.
38. method as claimed in claim 37 is characterized in that also comprising to described protected element sending the session request of selecting, and wherein when receiving described event information, optionally the incoming call session request is forwarded to described protected element.
39. one kind for element provides the session filter of dialogue control, it comprises:
A) at least one interface; With
B) control system, it is relevant with described at least one interface and be suitable for:
I) be received in the session request of setting up dialogue between protected element and at least one the source element;
Ii) receive the event information of the expression undesirable state relevant with described protected element;
Iii) handle described event information, so that determine some session request of selection; And
Iv) transmitting system protection response, described system protection response are suitable for stopping or reducing the many session request that produced by described at least one source element.
40. session filter as claimed in claim 39; it is characterized in that: described control system also is suitable for sending the session request of selecting to described protected element; wherein, when receiving described event information, optionally the incoming call session request is forwarded to described protected element.
CNA2004100456631A 2003-05-16 2004-05-17 Method and apparatus for session control Pending CN1551605A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/439531 2003-05-16
US10/439,531 US7590122B2 (en) 2003-05-16 2003-05-16 Method and apparatus for session control

Publications (1)

Publication Number Publication Date
CN1551605A true CN1551605A (en) 2004-12-01

Family

ID=33029815

Family Applications (1)

Application Number Title Priority Date Filing Date
CNA2004100456631A Pending CN1551605A (en) 2003-05-16 2004-05-17 Method and apparatus for session control

Country Status (3)

Country Link
US (1) US7590122B2 (en)
EP (1) EP1478157A1 (en)
CN (1) CN1551605A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101513013B (en) * 2006-09-11 2012-12-12 艾利森电话股份有限公司 System and method for overload control in a next generation network
CN102177690B (en) * 2008-07-31 2014-09-03 泰克莱克股份有限公司 Methods, systems, and computer readable media for providing sedation service in a telecommunications network

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7437409B2 (en) * 2003-06-13 2008-10-14 Microsoft Corporation Limiting interaction between parties in a networked session
US7765302B2 (en) * 2003-06-30 2010-07-27 Nortel Networks Limited Distributed call server supporting communication sessions in a communication system and method
GB2422995B (en) * 2003-11-04 2007-07-18 Ntt Comm Corp Method, apparatus and program for establishing encrypted communication channel between apparatuses
US20050114514A1 (en) * 2003-11-21 2005-05-26 Bostrom Kevin L. Advising a network component for control of communication session connection through employment of one or more communication session restrictions
US20060187901A1 (en) * 2005-02-23 2006-08-24 Lucent Technologies Inc. Concurrent dual-state proxy server, method of providing a proxy and SIP network employing the same
US7680037B2 (en) * 2005-03-01 2010-03-16 Alcatel-Lucent Usa Inc. Resource-sensitive parser, method of parsing and session initiation protocol (SIP) network employing the same
US20060215634A1 (en) * 2005-03-25 2006-09-28 Marian Croak Method and apparatus for processing a call from an endpoint device in a packet network
EP1955483A4 (en) * 2005-11-29 2013-05-15 Cisco Tech Inc System and method for handling network overload
US7756034B2 (en) * 2005-11-29 2010-07-13 Cisco Technology, Inc. System and method for handling network overload
US7760639B2 (en) * 2005-11-29 2010-07-20 Cisco Technology, Inc. System and method for handling network overload
US8315162B2 (en) 2006-08-24 2012-11-20 Research In Motion Limited System and method for determining that a maximum number of IP sessions have been established
ES2317445T3 (en) * 2006-08-24 2009-04-16 Research In Motion Limited SYSTEM AND METHOD TO DETERMINE THAT A MAXIMUM NUMBER OF IP SESSIONS HAS BEEN ESTABLISHED.
US9253099B2 (en) 2006-09-11 2016-02-02 Telefonaktiebolaget L M Ericsson (Publ) System and method for overload control in a next generation network
US7441429B1 (en) * 2006-09-28 2008-10-28 Narus, Inc. SIP-based VoIP traffic behavior profiling
EP1906614B1 (en) 2006-09-28 2012-09-05 Siemens Enterprise Communications GmbH & Co. KG Method, communication terminal, connection controller and communication system for connections processing
EP1912386B1 (en) * 2006-10-13 2013-07-31 Research In Motion Limited System and method for managing IP sessions based on how many IP sessions are supported
US8687586B2 (en) * 2006-10-13 2014-04-01 Blackberry Limited System and method for managing IP sessions based on how many IP sessions are supported
US8611946B2 (en) * 2007-01-25 2013-12-17 Blackberry Limited Methods and systems for configuring multi-mode mobile stations
JP2008227917A (en) * 2007-03-13 2008-09-25 Hitachi Ltd Communication system and router
US20090022163A1 (en) * 2007-07-16 2009-01-22 Vladimir Oksman Adaptive network to dynamically account for hidden nodes
EP2202938A1 (en) * 2008-12-24 2010-06-30 Mitsubishi Electric R&D Centre Europe B.V. Protection against flooding attacks in a network
WO2011063844A1 (en) * 2009-11-26 2011-06-03 Telefonaktiebolaget Lm Ericsson (Publ) Method, system and network nodes for performing a sip transaction in a session initiation protocol based communications network
US8335847B2 (en) * 2010-07-30 2012-12-18 Guest Tek Interactive Entertainment Ltd. Method of servicing requests to manage network congestion and server load and server thereof
GB2489447B (en) 2011-03-28 2018-05-30 Metaswitch Networks Ltd Telephone call processing method and apparatus
WO2016038586A1 (en) * 2014-09-12 2016-03-17 Telefonaktiebolaget L M Ericsson (Publ) Methods and systems for controlling congestion in a communication network
US11416448B1 (en) * 2019-08-14 2022-08-16 Amazon Technologies, Inc. Asynchronous searching of protected areas of a provider network

Family Cites Families (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5572442A (en) * 1994-07-21 1996-11-05 Information Highway Media Corporation System for distributing subscription and on-demand audio programming
CA2242596C (en) * 1996-01-11 2012-06-19 Mrj, Inc. System for controlling access and distribution of digital property
US5754786A (en) 1996-09-13 1998-05-19 At&T Corp System and method for integrated overload control and message distribution
US5987331A (en) * 1996-11-20 1999-11-16 Motorola, Inc. Communication system to communication system gateway method and apparatus
US6119143A (en) * 1997-05-22 2000-09-12 International Business Machines Corporation Computer system and method for load balancing with selective control
US6256771B1 (en) * 1997-10-16 2001-07-03 At&T Corp. Method and apparatus for providing a dynamic service composition software architecture
US6219346B1 (en) * 1997-12-02 2001-04-17 At&T Corp. Packet switching architecture in cellular radio
US6370234B1 (en) * 1998-06-16 2002-04-09 Kroll Family Trust Public service answering point with automatic triage capability
US6490624B1 (en) * 1998-07-10 2002-12-03 Entrust, Inc. Session management in a stateless network system
US6360270B1 (en) * 1998-11-16 2002-03-19 Hewlett-Packard Company Hybrid and predictive admission control strategies for a server
US6182149B1 (en) * 1999-01-11 2001-01-30 3Com Corporation System for managing dynamic processing resources in a network
EP1111894A1 (en) * 1999-12-22 2001-06-27 Telefonaktiebolaget Lm Ericsson Communication system and method for establishing a conversation using different link layer thechnologies
US6944150B1 (en) * 2000-02-28 2005-09-13 Sprint Communications Company L.P. Method and system for providing services in communications networks
KR20010092616A (en) * 2000-03-22 2001-10-26 오지수 Data processing method and device for VDD system supporting a renting system based on a given period of time
GB2361389B (en) * 2000-04-15 2004-01-28 Ericsson Telefon Ab L M Telecommunications system
US6898278B1 (en) 2000-05-08 2005-05-24 Li Li Signaling switch for use in information protocol telephony
US6868450B1 (en) * 2000-05-17 2005-03-15 Hewlett-Packard Development Company, L.P. System and method for a process attribute based computer network filter
US20020049930A1 (en) * 2000-09-07 2002-04-25 Inrange Technologies Corporation Protocol analysis framework
US6801948B2 (en) * 2000-12-15 2004-10-05 Hewlett-Packard Development Company, L.P. System and method for a streams based network access control for a computer
US7032243B2 (en) * 2000-12-15 2006-04-18 Hewlett-Packard Development Company, L.P. System and method for a group-based network access control for computer
US7218722B1 (en) * 2000-12-18 2007-05-15 Westell Technologies, Inc. System and method for providing call management services in a virtual private network using voice or video over internet protocol
US7171678B2 (en) * 2001-01-22 2007-01-30 N2 Broadband, Inc. Systems and methods for establishing and administering sessions in digital cable systems
US6904521B1 (en) * 2001-02-16 2005-06-07 Networks Associates Technology, Inc. Non-repudiation of e-mail messages
US6944133B2 (en) * 2001-05-01 2005-09-13 Ge Financial Assurance Holdings, Inc. System and method for providing access to resources using a fabric switch
US7136386B2 (en) * 2001-07-19 2006-11-14 Sbc Technology Resources, Inc. Virtual private network over asynchronous transfer mode
US6885874B2 (en) * 2001-11-27 2005-04-26 Motorola, Inc. Group location and route sharing system for communication units in a trunked communication system
US7539186B2 (en) * 2003-03-31 2009-05-26 Motorola, Inc. Packet filtering for emergency service access in a packet data network communication system
US7342918B2 (en) * 2003-04-15 2008-03-11 American Express Travel Related Services Co., Inc. Transaction card information access web service

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101513013B (en) * 2006-09-11 2012-12-12 艾利森电话股份有限公司 System and method for overload control in a next generation network
CN102177690B (en) * 2008-07-31 2014-09-03 泰克莱克股份有限公司 Methods, systems, and computer readable media for providing sedation service in a telecommunications network

Also Published As

Publication number Publication date
US20040228352A1 (en) 2004-11-18
EP1478157A1 (en) 2004-11-17
US7590122B2 (en) 2009-09-15

Similar Documents

Publication Publication Date Title
CN1551605A (en) Method and apparatus for session control
CN100508539C (en) Implement method and system for double-home of session boundary controller
EP0973343B1 (en) Optimum routing of calls over the public switched telephone network and the internet
US20020176405A1 (en) Cost control in a SIP based network
EP1109368A2 (en) System, method and computer program product for support of bearer path services in a distributed control network
US20140241342A1 (en) Emergency services for packet networks
EP1606921B1 (en) Request redirection handling in imc
CN1498491A (en) Caller treatment in SIP network
WO2002028047A2 (en) Generic call server and method of converting signaling protocols
CN1574985A (en) Server component redirection of new media path portion between packet-switched and circuit-switched portions of mobile switching center
CN1893435A (en) SIP server, terminal device, subscriber information management device and communication control method
US20160135030A1 (en) System and method for monitoring communications in a network
EP1093312B1 (en) Correlation of signalling messages
GB2369262A (en) Call looping prevention
EP1654621B1 (en) System and method for monitoring communications in a network
EP1436963B1 (en) Method, apparatus and computer program for selecting a media gateway control function based on the monitoring of resources of media gateway functions
CN1870521A (en) Method for reducing service lossing of SS7 signalling and M3UA communicating
CN100589641C (en) A method for preventing call session control function entity from active resource hangup
CN1859517A (en) Click-to-call system of network telephone and its control method
CN1878335A (en) Method of setting up calls between a calling terminal and a called terminal
KR100673165B1 (en) Method And System Of Redirecting Call/Session Based On SIP When Called Party Is Busy
Whitehead GOCAP--one standardised overload control for next generation networks
KR100488817B1 (en) Method And System Of Redirecting Call/Session Based On SIP When Called Party Is Not Reachable
KR100629889B1 (en) Method And System Of Redirecting Call/Session Based On SIP
JP4330584B2 (en) Request redirection handling in IMC

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C02 Deemed withdrawal of patent application after publication (patent law 2001)
WD01 Invention patent application deemed withdrawn after publication